I've been eyeing that one for a while and everytime I decide to go for it I watch a video review of the pen and change my mind. It's certainly an interesting pen but it doesn't match how I use my pens (mainly note taking so using the mechanism would get old). I've also heard they aren't the easiest to clean but haven't heard that from someone who actually owned the pen.
You clean them by flushing thru a long cartridge that's been hollowed out at the rear, use the cartridge as a nozzle for your bulb syringe.
Biggest sin is getting the mechanism wet & putting it away damp; the insides are steel and will rust.
Mine sees daylight about once every 5yrs
a new cartridge, then a bit of use until dry then gets flushed. Is left opened out to dry for about a week before going back in its box.
Nice mechanism design but it's a gimmick imho & gets in the way of my usual writing workflow. I don't post & I don't have patience to go twisting the knob to extend nib just to jot the odd note. I haven't handwritten long essays or multi page letters for decades.
Hmm... might be time to dig it out again